| 摘要 |
PURPOSE:To compress and harden the entire part of green sand and to mold a green sand core having an intricate shape by packing the green sand in the cavity of a core box having open end face parts in >=2 places, and inserting a bar member having the tip formed into approximately an inverted cone shape through >=1 open parts and a pressing member through the other open part. CONSTITUTION:An auxiliary member 4 having the same auxiliary cavity 3 of which the internal size is the same as that of an open bottom end 1b is concentrically attached to the bottom surface of a core box 2 of vertically split molds having an open top end 1a and the open bottom end 1b. Green sand S is packed in cavities 1, 3 and a bar member 5 having the tip formed into an approximately inverted conical shape is inserted into the cavity through the end 1a to compress the sand S by 10-50%; at the same time, a pressing member 6 is fitted into the cavity 3 of the member 4 to force the sand S in the cavity 3 into the cavity 1. The sand S is compressed and hardened in such a way and thereafter the member 5 and the member 6 are removed and the core box is opened, whereby a hollow-shaped core is obtd. The resulted core has a good shape retentivity, a good collapsing property and vents satisfactorily gas. |
